Want to immigrate to Mars? You have to pass through cosmic rays first.

As we all know, one of the key factors why the earth we live in has become a paradise for life is the protection of the earth's magnetic field.

The earth's magnetic field and atmosphere effectively shielded the harm of high-energy particle flow and cosmic rays from the sun to the earth, and made great contributions to the birth of life on earth.

But our neighbor Mars is not so lucky. Billions of years ago, the core of Mars cooled, causing the magnetic field to disappear. Without the protection of magnetic field, the violent solar wind directly destroyed the atmosphere of Mars, and the water on the surface evaporated.

| Mars heat continues to heat up

In this July, mankind set off a craze for Mars exploration. The United Arab Emirates, China and the United States have successively launched probes to Mars. Even the United Arab Emirates has announced its own manned landing plan on Mars, hoping to establish its first permanent human settlement on Mars in 2 1 17. Of course, "Iron Man" Musk has not been idle, and Musk's Mars landing plan has also been in preparation.

When people are eager to try and look forward to the future of Mars, I have to throw a pot of cold water here first.

The other side of the sun

Because, when humans immigrate to Mars, they must first experience solar flare explosion and cosmic ray radiation.

As we all know, the sun is actually a huge thermonuclear reaction furnace, and this furnace is not always stable. It occasionally sneezes (solar flare bursts) and loses a small temper (high-energy particle jet). Of course, we live in the earth's atmosphere and may not feel it. But if you are in space without the protection of the earth's magnetic field, you will really feel the other side of the sun.

Flare burst is the strongest solar activity on the solar surface, and the burst period is about 1 1 year. Every big flare will raise the brightness of the flare area to a very high level in a few minutes or dozens of minutes, and then gradually dim.

The energy produced by a large flare explosion is equivalent to tens of billions of giant hydrogen bombs exploding at the same time. Sometimes, although the earth is protected by a magnetic field, it will also be affected. For example, in 20 14, solar flares broke out three times in June of 10 and June of10/year, temporarily interrupting some high-frequency radio communication on the earth.

The huge energy generated by the flare will also accelerate the material particles in the corona to near the speed of light and throw them out. These high-energy particles will soon reach the region where the Earth and Mars are located. Of course, when a flare breaks out, astronauts will be much safer if they are not exposed to space and protected by spacecraft. However, compared with us earthlings, the radiation dose received by astronauts who have been performing space missions for a long time will easily exceed the limit.

Cosmic high-energy rays

In fact, when exposed to space, the radiation received by the human body is not all from the sun, but also from high-energy cosmic rays.

Because some of the high-energy particle streams produced by these supernova explosions are high-energy particles of heavy elements, their penetrating power is far greater than that produced by solar flares. It can penetrate the spacecraft shell and radiate to the astronauts inside. Unlike the periodic bursts of solar flares, supernova explosions in the Milky Way have great uncertainty and universality. It will last forever.

Life on earth seems to have no feeling for cosmic high-energy rays. This is not only due to the earth's magnetic field and atmosphere, but also due to the protection of the sun. The solar system also has a galactic magnetic field, which has a certain shielding effect on cosmic rays.

It is best to live on Mars or underground.

However, if humans land on Mars in the future, once they enter space, they will lose the protection of the earth's magnetic field and atmosphere, and be exposed to the radiation environment of the sun and high-energy rays of the universe for several months, which is extremely risky.

In addition, after landing on Mars, because there is no magnetic field on Mars, the atmosphere is very thin, only 1% of the earth's. On the surface of Mars, human beings are still influenced by solar wind and cosmic rays.

To this end, NASA has done some calculations. During the 20 12 trip to Mars, Curiosity carried a "Radiation Assessment Detector" (RAD) to measure the radiation level during and after landing on Mars.

The results show that an astronaut may be exposed to 0.662 sieverts during the journey to and from Mars for more than 1 year, which is equivalent to 62% of the total extreme radiation received by NASA during the astronaut's whole career. This is just a round trip, not including the radiation received on the surface of Mars after human landing.

According to the data sent back by the probe before, the average radiation level on the surface of Mars is 2.5 times that of astronauts on the International Space Station and 13 times that of the Earth. Long-term exposure to such radiation environment, human health is worrying.

There are still many things to be done to realize the permanent residence of human beings on Mars.

Of course, if humans want to land on Mars and build long-term settlements. The radiation problem is only one of the difficulties, and there are more problems to be solved.

For example, the fuel refining problem needed for the return trip, the continuous supply of water and food, the changes of human physiology in low gravity environment, and even the social problems caused by more people, as well as the handling of the relationship between Mars and the earth, and so on. Not a company or an organization can do it overnight. These problems need the joint efforts of all countries in the world to achieve.

So, let's take a look at the commercial PPT of Musk's permanent residence on Mars and get excited. Only the blueprint and frame are set, which is a title. To write a good article, it depends on how to write every word below. Of course, we believe that as long as human beings are United enough and spend enough time, these problems will eventually be solved.

Maybe people living on Mars in the future should look at the radiation warning index in the weather forecast of Mars before going out.